Description of Alloy C22 Tube/Pipe
ALLOY22 is a Ni-Cr-Mo alloy with tungsten and very low levels of carbon and silicon. The high chromium content contributes to resistance against oxidising media. Molybdenum and tungsten contribute to resistance against reducing media. This nickel steel alloy resists oxidising aqueous media, including wet chlorine and mixtures that contain nitric acid or oxidising acids with chloride ions. It also resists oxidising acid chlorides, wet chlorine, formic acid, acetic acid, iron and copper chlorides, sea water, brine and many mixed or contaminated chemical solutions, both organic and inorganic. The alloy withstands both reducing and oxidising conditions in process streams. This performance is critical in multi-purpose facilities where such conditions occur.
This nickel alloy resists the formation of grain boundary precipitates in the heat-affected zone of welds. It is therefore suitable for most chemical process applications in the welded condition.
Alloy C-22 should not be used at operating temperatures above 1250°F, as detrimental phases form above this temperature.

Specifications for Alloy C22 Pipes
Chemical Composition in %
|
Ni
|
Cr
|
Mo
|
Mn
|
Si
|
C
|
S
|
P
|
Cu
|
V
|
W
|
Fe
|
Minimum
|
-
|
20.0
|
12.5
|
-
|
-
|
-
|
-
|
-
|
-
|
-
|
2.5
|
-
|
Maximum
|
Equilibrium
|
22.5
|
14.5
|
0.5
|
0.08
|
0.015
|
0.02
|
0.02
|
2.5
|
0.35
|
3.5
|
6.0
|
ASTM Specifications
Pipes
|
Tube
|
Sheet/Plate
|
Bar
|
Forgings
|
Fitting
|
B622/619
|
B626
|
B575
|
B574
|
B564
|
B366
|
Applications of Alloy C22 Pipe/Pipe
- Flue Liner:
- The alloy’s measured corrosion resistance in both oxidising and reducing environments complies with technical specifications. This ensures acceptable durability in flue liners.
- Pipes:
- The alloy maintains channel integrity over extended periods. It exhibits resistance to oxidation and corrosion in various aggressive media.
- Dampers:
- Corrosion and oxidation resistance are quantitatively verified. This ensures consistent damper performance in environments with corrosive gases.
- Washers:
- The alloy resists chemical exposure. Quantitative tests confirm its ability to perform against pollutants and contaminant chemicals.
- Heat Exchangers:
- The alloy performs under both oxidising and reducing conditions. Its thermal stability and measured performance ensure prolonged operational life.
- Reaction Vessels:
- The alloy resists a range of corrosive substances, including acids and chlorides. This supports the structural integrity of reaction vessels.
- Evaporators:
- The alloy’s resistance to corrosion in environments with concentrated solutions and corrosive substances is confirmed by testing. This ensures reliable evaporator performance over time.